Liquids are often sold in containers with lids, caps or valves that allow a user to remove some of the liquid contents of the container through an opening, but retain the remainder of the contents in the container for future use. Such retention generally requires that the container provide a mechanism to re-seal the opening to prevent the liquid from escaping through the opening, either by spillage or evaporation, and to prevent spoilage of the liquid through exposure to the outside environment. Examples of such liquids include toothpaste, cosmetic cream, shampoo, glue, washing detergents, and various food items, such as tomato paste, peanut butter, chocolate paste, and icing.
Re-sealing of such containers generally requires the replacement of a cap that covers a dispensing nozzle having an opening through which the liquid passes. Such approaches are undesirable because of the need for a user to manipulate the cap to re-seal the opening.
Some approaches have been devised to provide a self-sealing nozzle that allows a user to squeeze the container to pressurize the liquid contained therein so that the liquid applies pressure to the nozzle, causing it to open and allow the liquid to pass though the opening, and then to re-seal the opening automatically when the pressure is removed. While such a capability is highly desirable to users, existing devices to provide such a capability have been generally unsuccessful for various reasons such as complexity, cost, cleanliness, and inadequate isolation of the liquid in the container from the outside environment.